AB1410 ASSOCIATION BETWEEN MUSCLE MASS PERCENTAGE WITH PAIN AND DISABILITY IN PATIENTS WITH NON-SPECIFIC CHRONIC LOW BACK PAIN: THE BACKFIT PROJECT
Authors: Y. M. Gil-Gutiérrez, G. Tsiarleston, B. Donoso, M. Delgado-Fernández, M. Y. Castellote-Caballero, V. Segura-Jiménez
Journal: Annals of the Rheumatic Diseases (2023)

<h3>Background</h3> Non-specific chronic low back pain (NSCLBP) is one of the most common musculoskeletal disorders worldwide<sup>[1]</sup>. Recent studies have shown higher levels of pain<sup>[2,3]</sup> and disability<sup>[4]</sup> in patients with NSCLBP who presented higher body mass index. However, the relationship between body muscle mass and these two variables is unknown. <h3>Objectives</h3> To determine if there is an association of body muscle mass percentage with pain and disability in patients with NSCLBP. <h3>Methods</h3> 105 patients (70 women, 50.59 ± 9.95 years) participated in this cross-sectional study. Body muscle mass percentage was evaluated using portable bioimpedance of eight tactile polar electrodes (InBody R20). Pain sensitivity threshold was assessed using manual pressure algometry (FPK 20, Wagner Instruments, Greenwich, CT, USA). Pain intensity was evaluated using two instruments, on the one hand a visual analogue scale (VAS) and on the other hand the pain dimension of the Short-Form Health Survey-36 (SF-36) questionnaire. The Oswestry Low Back Pain Disability questionnaire was used to assess disability due to pain. To study the association between the main variables, a linear regression analysis was carried out, controlling for age, sex, marital and educational status, time since clinical diagnosis and waist circumference as covariates using the 'stepwise' method. As there was no interaction in terms of sex, the analyses were carried out jointly (women and men). <h3>Results</h3> Higher levels of body muscle mass percentage were associated with higher pain sensitivity threshold (<i>b</i>=0.071; 95% confidence interval (CI)= 0.017,0.130; <i>p</i>=0.017, lower VAS-pain (<i>b</i>=-0.095; 95% CI= -0.184, -0.007; <i>p</i>=0.03) and higher score in the SF-36 pain dimension (<i>b</i>=1.038; 95% CI= 0.376, 1.701 <i>p</i>=0.002), and lower disability due to pain (<i>b</i>= -1.028; 95% CI= -1.513, -0.542; <i>p</i>&lt;0.001). <h3>Conclusion</h3> Patients with NSCLBP presenting higher body muscle mass percentage showed lower pain and disability due to pain, and higher pain sensitivity threshold. Further intervention studies are necessaries to check the effects on pain and disability of programs focused on improving muscle mass in this population. <h3>References</h3> <b>[1]</b> Abdollahi M, Ashouri S, Abedi M, Azadeh-Fard N, Parnianpour M, Khalaf K, et al<i>. Using a Motion Sensor to Categorize Nonspecific Low Back Pain Patients: A Machine Learning Approach. Sensors</i> [Internet] 2020;20 (12): 3600-3616. <b>[2]</b> Chou L, Brady S.R, Urquhart D.M, Teichtahl A.J, Cicuttini F.M, Pasco J.A, Wluka A.E. <i>The association between obesity and low back pain and disability is affected by mood disorders: a population-based, cross-sectional study of men</i>. Medicine 2016; <i>95</i>(15):1-7. <b>[3]</b> Urquhart D.M, Berry P.B,Wluka, A.E, Strauss B.J, Wang Y, Proietto J, et al. <i>2011 Young Investigator Award Winner:</i>Increased Fat Mass Is Associated With High Levels of Low Back Pain Intensity and Disability. Spine 2011; 36(16): 1320-1325. <b>[4]</b> Teck T.S, Prabowo T, Kurniani N. <i>Correlation between Body Mass Index and Disability in patient with Chronic Low Back Pain.</i> Althea Medical Journal 2016; 3(4): 624-628. <h3>Acknowledgements</h3> The authors thank all the researcher involved in the fieldwork. Participants are deeply acknowledged for their collaboration and great enthusiasm during the development of the study. This study was supported by the Instituto de Salud Carlos III through the reserch contract Miguel Servet (CP20/00178) co-funded by European Social Fund. Furthermore, BD-P was supported by the "Margarita Salas" postdoctoral grant UCOR01MS. <h3>Disclosure of Interests</h3> None Declared.